# Categories

Categories sort films in mint, in two levels: categories and subcategories. Link them to your own structure with
`external_key`, for example a course code, and use that key when you order a film (`category.external_key`).
Creating a category with an `external_key` that already exists returns the existing category.

## Endpoints

- `GET /v1/categories`: List the category tree
- `POST /v1/categories`: Create a category or subcategory
- `PATCH /v1/categories/{id}`: Rename a category or change its external key